Multifunctional catalyst for the conversion of carbon dioxide

Abstract

The present invention concerns a multifunctional catalyst for the conversion of CO2 into useful products, such as CO via the reverse water gas shift reaction. The catalyst according to the invention efficiently combined a water sorption functionality with at least one catalytic functionality into a single particle, by having a solid water sorbent impregnated with at least one metal capable of converting CO2 from a gaseous mixture comprising H2 and CO2. The catalyst according to the invention allows for higher selectivity in the conversion of CO2, at more lenient conditions in terms of temperature and pressure, and improved stability of the catalyst itself. The invention also concerns a process for converting CO2, utilizing the catalyst and the use of the catalyst in the conversion of CO2.

1 .- 15 . (canceled) 
     
     
         16 . A multifunctional catalyst, comprising a solid water sorbent impregnated with at least one metal capable of catalyzing the conversion of CO2 from a gaseous mixture comprising H2 and CO2, wherein the sorbent is a molecular sieve having a Si/Al molar ratio below 50 and containing pores having a diameter in the range of 3 to 20 Å and the metal content in the catalyst is not more than 40% based on total weight of the multifunctional catalyst. 
     
     
         17 . The multifunctional catalyst according to  claim 16 , wherein the sorbent has a Si/Al molar ratio in the range of 1 and 2. 
     
     
         18 . The multifunctional catalyst according to  claim 17 , wherein the sorbent has a Si/Al molar ratio is 1. 
     
     
         19 . The multifunctional catalyst according to  claim 16 , wherein the sorbent is a zeolite selected from LTA zeolite, X-type zeolite and mixtures thereof. 
     
     
         20 . The multifunctional catalyst according to  claim 19 , wherein the sorbent component comprises LTA-4A zeolite and/or zeolite 13×. 
     
     
         21 . The multifunctional catalyst according to  claim 16 , wherein the pores have a diameter in the range of 4 to 8 Å. 
     
     
         22 . The multifunctional catalyst according to  claim 16 , wherein the internal and external surfaces of the sorbent are impregnated with the at least one metal catalyst, and/or wherein the sorbent is impregnated with 0.1-40 wt %, based on total weight of the multifunctional catalyst. 
     
     
         23 . The multifunctional catalyst according to  claim 16 , wherein the at least one metal is selected from the group consisting of Pt, Cs, Cu, Rh, Au, Zn, Co, Fe, Mo, Zn, Mn, Ru, Ir, Os, Ag, Al, Cr, Li, Na, K, Rb, Cs, Ce, Re, In, Zr, Ni, Mg, Al, Pd, Ga and mixtures thereof. 
     
     
         24 . The multifunctional catalyst according to  claim 23 , wherein the at least one metal is selected from the group consisting of Pt, Zn, Fe, Cs, Cu and mixtures thereof. 
     
     
         25 . The multifunctional catalyst according to  claim 16 , wherein the solid sorbent is further impregnated with a second metal capable of catalyzing the synthesis of dimethyl ether from methanol or diethyl ether from ethanol. 
     
     
         26 . The multifunctional catalyst according to  claim 16 , wherein the solid sorbent is impregnated with the metal by wet impregnation. 
     
     
         27 . A process for the conversion of CO2 from a gaseous feedstock comprising H2 and CO2, comprising the step of subjecting the gaseous feedstock to a multifunctional catalyst, comprising a solid water sorbent impregnated with at least one metal capable of converting CO2 from a gaseous mixture comprising H2 and CO2, wherein the sorbent is a molecular sieve having a Si/Al molar ratio below 50 and containing pores having a diameter in the range of 3 to 20 Å and the metal content in the catalyst is not more than 40% based on total weight of the multifunctional catalyst. 
     
     
         28 . The process according to  claim 27 , wherein the conversion of CO2 involves a reverse water gas shift reaction (RWGS) to form CO, a hydrogenation reaction to form methanol or ethanol, or a Fisher-Tropsch reaction to form alkanes, a Fisher-Tropsch reaction to form alkenes, a Methanol to Olefins (MTO) reaction to form alkenes, an aromatization reaction to form aromatic hydrocarbons or a hydrogenation reaction to form methane, optionally wherein the hydrogenation reaction is accompanied with a dehydration reaction to convert methanol into dimethyl ether or ethanol into diethyl ether. 
     
     
         29 . The process according to  claim 28 , wherein the conversion is a RWGS reaction. 
     
     
         30 . The process according to  claim 27 , wherein the process takes place at a temperature in the range of 100-500° C., and/or wherein the reaction takes place at a pressure in the range of 0.5-20 MPa. 
     
     
         31 . The process according to  claim 27 , wherein the molar ratio of H2 to CO2 in the feedstock is in the range of 10:1-1:5 and/or wherein the feedstock further comprises CO. 
     
     
         32 . The process according to  claim 27 , further comprising a regeneration step of the catalyst wherein the pressure is reduced by at least 0.1×106 Pa and/or the temperature is increased by at least 20° C. 
     
     
         33 . The process according to  claim 27 , wherein the sorbent component comprises LTA-4A zeolite and/or zeolite 13×. 
     
     
         34 . The multifunctional catalyst according to  claim 23 , wherein the at least one metal is selected from the group consisting of Pt, Zn, Fe, Cs, Cu and mixtures thereof. 
     
     
         35 . The multifunctional catalyst according to  claim 16 , wherein the solid sorbent is impregnated with the metal by wet impregnation.